 
 (deftest very-basic-types
   (is (= 1 1))
+  ;; Lots of things are truthy, which is the simplest?
   (is (true? true))
+  ;; Now what is the concatenation of those Characters
   (is (= (str \a \b \c) "abc"))
   ;; Use vector literal
   (is (= '(1 2 3) [1 2 3]))



(deftest how-to-find-length-of-something
  (let [f count]
    (are [x y] (= x y)
      (f '(1 2 3 3 1)) 5

    (filter even? '(1 2 3 4 5)) '(2 4)))


(deftest define-a-function-that-checks-string-longer-than
  (let [longer-than? (fn [str len] (> (count str) len))]
    (are [x y] (= x y)
         (longer-than? "long string" 5) true
         (longer-than? "short" 5) false
         (longer-than? nil 2) false)))


(deftest use-map-to-double-all-numbers-in-a-sequence
